He was recruited for the Manhattan Project in 1941, and was in Project Alberta on the dropping of the bomb. When the Los Alamos lab was first being organised a decision was made by Oppenheimer to not compartmentalize the technical information among different departments. This increased the effectiveness of the technical workers in problem solving, and emphasized the urgency of the project in their minds, now they knew what they were working on. So it fell to Serber to give a series of lectures explaining the basic principles and goals of the project. These lectures were printed and supplied to all incoming scientific staff, and became known as The Los Alamos Primer, LA-1. It was declassified in 1965. (Available at Wikimedia Commons). Serber developed the first good theory of bomb disassembly hydrodynamics.

Serber created the code-names for all three design projects, the "Little Boy" (uranium gun), "Thin Man" (plutonium gun), and "Fat Man" (plutonium implosion), according to his reminiscences (1998). The names were based on their design shapes; the "Thin Man" would be a very long device, and the name came from the Dashiell Hammettdetective novel and series of movies of the same name; the "Fat Man" bomb would be round and fat and was named after Sidney Greenstreet's character in The Maltese Falcon. "Little Boy" would come last and be named only to contrast to the "Thin Man" bomb. This differs from the alternative theory that "Fat Man" was named after Churchill and "Thin Man" after Roosevelt (see Links).

Serber was to go on the camera plane for the Nagasaki mission, Big Stink, but it left without him when Major Hopkins ordered him off the plane as he had forgotten his parachute, reportedly after the B-29 had already taxied onto the runway. Since Serber was the only crew member who knew how to operate the high-speed camera, Hopkins had to be instructed by radio from Tinian on its use.

Serber was with the first American team to enter Hiroshima and Nagasaki to assess the results of the atomic bombing of the two cities.

In 1947 an attempt was made on his life by anti-communist librarian Chris James Hines and in 1948, he had to defend himself against anonymous accusations of disloyalty, mostly due to the fact that his wife's family were Jewish intellectuals with Socialist leanings, and also because he tried to remove politics from discussions of the feasibility of the fusion bomb, leading to arguments with Edward Teller.

Serber went on to be consultant to numerous labs, businesses and commissions.

Robert Serber is interviewed in the Oscar-nominated documentary, The Day After Trinity (1980). In the 1989 movie dramatization of the Manhattan Project, Fat Man and Little Boy, the role of Robert Serber was played by Dr. H. David Politzer, a Professor of Theoretical Physics at Caltech. Serber is probably the only prominent physicist in history to have been portrayed on screen by an actual prominent physicist: Dr Politzer was awarded the Nobel Prize in Physics in 2004.

References

Serber, Robert, with Robert P. Crease, Peace and War: Reminiscences of a Life on the Frontiers of Science, (New York: Columbia University Press, 1998), ISBN 0-231-10546-0, LoC QC16.S46A3 1998

Serber, Robert, The Los Alamos Primer: The First Lectures on How to Build an Atomic Bomb, (University of California Press, 1992) ISBN 0-520-07576-5 Original 1943 "LA-1", declassified in 1965, plus commentary and historical introduction.